The present invention relates to a coaxial connector element and, more particularly, to a coaxial connector element of the direct sealing type, i.e., one comprising a tubular body having an inner cavity, a rod secured against axial motion in said body by a bead made from dielectric material, particularly glass, said axial rod protruding from the tip of said body closed by said bead, a central contact having an axial hollow for its engagement around said rod within said body, and an insulator between said central contact and the wall of the cavity within said body.
This type of connector element is generally employed in microelectronics for microwave applications, and they are usually assembled in a box, their axial rod being connected, in particular, to a printed circuit board.
In order to obtain satisfactory electrical properties on the central contact of such connector elements, the central contact must be secured against motion on the axial rod, in such a way that the electrical connection is made right next to the tip of the central contact installed around the axial rod, i.e., near the bead made from glass or from a similar material and closing the tip of the connector element and through which said axial rod protrudes outwardly. This is an area which is difficult to reach during the fabrication process and to date the problems relating to the mechanical and electrical connections between the central contact and the axial rod have not yet been totally and satisfactorily resolved, all the more because it is particularly important for the opposite tip of the central contact to be accurately positioned in relation to a mechanical transversal reference plane for the engagement of a complementary contact.
A first presently known method for securing the central contact against motion on the axial rod consists in positioning a soldered joint near the tip of the central contact. Because of the location of the area where the soldering must be effected, the soldering operation is, in fact, done blindly so that, in practice, it is difficult to have any control over the quality of the soldered joint. In addition, this soldered joint is unreliable since, while the connector element is in use, it must be able to withstand temperatures of over 250.degree., because usually the other end of the axial rod is soldered at temperatures exceeding 250.degree. during the process of installing the connector element in a box.
A second presently known method is to use a mechanical means, such as a pair of pliers, in an attempt to secure the central contact against motion on the axial rod. This method is inadequate for securing the central contact against a translatory motion.